Separate a summer usage spike from a price change
Two 30-day bills show 330 kWh in spring and 540 kWh during a heat wave. A household wants to know whether the higher summer bill is consistent with a flat tariff.
Open CalculatorInputs and calculation
| Tool input | Value |
|---|---|
| Currency | USD |
| Utility | Electricity (kWh) |
| Previous usage | 330 |
| Current usage | 540 |
| Previous flat rate (USD/unit) | 0.24 |
| Current flat rate (USD/unit) | 0.24 |
| Previous bill (USD) | 91.2 |
| Current bill (USD) | 141.6 |
Usage: (540 − 330) × 0.24 = 50.4. Rate: 540 × (0.24 − 0.24) = 0. Actual bill difference: 141.6 − 91.2 = 50.4. Residual: 50.4 − (50.4 + 0) = 0. All effects are in USD.
Tool result · USD 50.40
| Tool input | Value |
|---|---|
| Currency | USD |
| Utility | Electricity (kWh) |
| Previous usage | 330 |
| Current usage | 480 |
| Previous flat rate (USD/unit) | 0.24 |
| Current flat rate (USD/unit) | 0.24 |
| Previous bill (USD) | 91.2 |
| Current bill (USD) | 127.2 |
Usage: (480 − 330) × 0.24 = 36. Rate: 480 × (0.24 − 0.24) = 0. Actual bill difference: 127.2 − 91.2 = 36. Residual: 36 − (36 + 0) = 0. All effects are in USD.
Tool result · USD 36.00
What the comparison shows
The observed figures imply 11 versus 18 kWh per day. A 60 kWh reduction would cut the modeled increase by 14.40.
Assumptions and limits
Weather and cooling are possible explanations. Appliance measurements or interval data are needed to attribute the extra load.
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